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Characterization of Zeolite Catalysts
Published in Subhash Bhatia, Zeolite Catalysis: Principles and Applications, 2020
An electron microprobe is useful for obtaining a profile of the distribution of heavy metals through a catalyst particle by working with a thin slice of the material or for detecting the build up of poisons and their distribution through individual pellets. It may also be used as an analytical method on a ground and representative sample of a catalyst which may be as small as 1 μm3. Electron microprobe analysis has been applied extensively to characterization of the promoted iron catalyst used in ammonia synthesis to show how certain promoters dissolve in magnetite during fusion and migrate to crystallite boundaries during reduction to iron metal. It is also used to identify segregation of rhodium at a surface of Pt-Rh alloy gauze used for the catalytic oxidation of ammonia.
Electron Sources
Published in Peter E. J. Flewitt, Robert K. Wild, Physical Methods for Materials Characterisation, 2017
Peter E. J. Flewitt, Robert K. Wild
The applications of the electron microprobe microanalysis are wide ranging and information obtained divides into two broad categories: (1) qualitative analysis usually presented as X-ray maps which allows the spatial relationship of the elemental distribution to be compared with that of the microstructure and (2) quantitative analysis where point counts are retrieved from predefined positions within the microstructure. Indeed, it is the computing power of the current generation instruments that provides hardware and specimen stage control as a prerequisite for mapping large areas of specimen and this is supported by the appropriate software for the data manipulation. Technological advances in recent years have exploited grey-level contrast differences between different parts of the image permit quantification and classification of features within it; this is discussed in detail in Chapter 7. Moreover, the computing power is now such that full quantitative analysis of selected locations are undertaken online.
1-xAs solar cell structures
Published in R D Tomlinson, A E Hill, R D Pilkington, Ternary and Multinary Compounds, 2020
F. Dimroth, A.W. Bett, G. Létay
Methods like electron microprobe [5] (also refered as x-ray microanalysis), nuclear reaction profiling [6] and Auger electron spectroscopy [7] were used by several authors to find the relationships mentioned above. Contrary results were published by these authors.
Effect and mechanism of modification treatment on ammonium and phosphate removal by ferric-modified zeolite
Published in Environmental Technology, 2019
Lin Gao, Chenyi Zhang, Yi Sun, Chuanming Ma
All samples were characterized by SEM, XRD, XRF and BET. Scanning electron microprobe (SEM) analysis was performed using a Japanese SU8010 electron microscope with an accelerating voltage of 15 kV. The mineral phase's identification was carried out by XRD using a Germany D8-FOCOS X-ray diffractometer with CuKα radiation and operating conditions were: 40 kV, 40 mA, a step width of 0.05° and 2θ range from 5° to 70°. The chemical compositions were determined by an XRF spectroscopy (the Netherlands, Panalytical B.V.AXIOSmAX). The specific surface area (SSABET) and pore volume were evaluated by the nitrogen gas adsorption at 77 K with an Automatic Volumetric Sorption Analyzer (ASAP2020, TSI, U.S.A.). Multipoint BET equation was employed to calculate SSABET and the Gurvich rule to calculate the total pore volume (Vtotal) based on the maximum adsorption amount of nitrogen at p/p0 = 0.97. In addition, the t-plot method was applied to calculate the microporous surface (SSAmic) and volume (Vmic). The average size of total pore and micropore (r and rmic, respectively) was determined by the relation r = 2 V/SSA with the assumption that the pore is in shape of a cylinder.
Atmospheric corrosion of ASTM A-242 and ASTM A-588 weathering steels in different types of atmosphere
Published in Corrosion Engineering, Science and Technology, 2018
Ivan Díaz, Heidis Cano, David Crespo, Belen Chico, Daniel de la Fuente, Manuel Morcillo
The techniques used to characterise the corrosion products layers were polarised light microscopy (PLM) to study rust stratification, scanning electron microscopy (SEM) to study the morphology of the corrosion products on the outermost surface of the rust layer, and X-ray diffraction (XRD) to determine the phases present in the rust. To observe any possible stratification of the rust layers formed on the different WS, use was made of a Nikon EPIP HOT 300 polarised light microscope coupled to an Infinity 2 camera. Analyses were performed on cross-sections of the specimens, always considering the skyward facing side. SEM studies were carried out on the skyward facing side of the exposed specimens using a JEOL JXA-840 electron microscope equipped with a Link System electron microprobe.
High-temperature oxidation resistance of Ni–P and Ni–B electroless coatings on mild steel after long-term tests
Published in Corrosion Engineering, Science and Technology, 2020
Juan G. Castaño, Sandra Arias, Oscar Galvis
Characterisation of un-coated and coated samples was performed before oxidation tests and after 400-hour oxidation tests. A JEOL JSM 6490-LV scanning electron microscope, coupled with an Oxford Inca PentaFET x-3 electron microprobe, was used to assess the morphology, elemental composition and thickness of the coatings before and after the oxidation tests, as well as the characteristic of the oxidation layers. On the other hand, the coatings and oxidation layers were analysed by means of X-ray diffraction (XRD) in a X’Pert PANalytical Empirean Series II diffractometer, model 2012, with a PIXcel 3D detector and Cu Kα anode radiation (0.1541874 nm). The data were collected in the 2ϴ range from 10° to 100°, at a scanning rate of 0.03° min−1.